Brake shoe dresser



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BRAKE SHOE DRESSER Filed May 8, 1939 3 Sheets-Sheet l :Iql

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BRAKE SHOE DRESSER Filed May 8, 1939 3 Sheets-Sheet 3 Patented Feb. 4, 1941 PATENT OFFICE 2,230,824 BRAKE suoliy DnEssER Harry K. Bigelow, Columbus, Ohio, assgnor of one-half to Benjamin S. Lurie, Columbus,

` Ohio Application May s, 1939, serial No. 272,451

5 Claims.

This invention relates to method and apparatus for acting upon surfaces of special contour.

This invention has utility when having to do with brake shoes, more especially for motor vehicles in conditioning or reconditioning such shoes, usually as to shoes of arc form to be operated within the overhang of a brake drum.

Referring to the drawings:

Fig. 1 is a side elevation of an embodiment of the invention as a power tool for readily operating on brake shoes;

Fig. 2 is a plan View of the device of Fig. 1; Fig. 3 is a section on the line III-III, Fig. 2,

, showing the abrading wheel and brake shoe mounting features;

Fig. 4 is a section on the line IV-1'V, Fig. 3, showing the eccentric mounting for the oscillator carrier for the brake shoe;

Fig. 5 is a section on the lineV-V, Fig. 3,

' showing the window to the abrader wheel or disk;

Fig. 6 is a view from the right of Fig. 1, certain parts being broken away;

Fig. 7 is a section on the line VIL-VII, Fig. 3, showing the carrier for the brake shoe Fig. 8 is a section on the line VIII- VIIL Fig. 1; and

Fig. 9 is a perspective View of the two arm mounting for the clamp from which the fingers extend.

Base or frame I (Fig. 1) has an upstanding portion 2 providing parallel guides 3 as a deck upon which is mounted complementary guide member 4 actuable by threaded screw stem A5 for adjustment to and fro upon rotation of hand wheel 6. This complementary guide member 4 or table section has mounted thereon by bolts 1 motor 8 having a shaft 9. Yieldable holding of this adjustable motor section is effected through threaded stem I (Fig. 3) having thereon compression heli- 'cal spring II between washers I2 which may be adjusted by nuts I3. This shaft 9, protruding from the motor 8, has xed thereon disk I4 having radiating fan blades I5. On th-e opposite face this disk I4 has adhesively attached thereto sand paper or emery cloth I6. Bolts I1 from the motor 3 carry a housing I8, to which is connected by wing bolts I9 a front plate 28 having a radial window 2l (Fig. 5) with a scoop extension 22 along the lower portion thereof. Accordingly, during the counter-clockwise rotation of this abrading disk I6 the material removed from th-e work is drawn by suction of the fan blades I to be expelled through duct 23.

The frame or base I additionally has a riser portion 24 spaced by a dip portion 25 from the upright 2. There .is thus clearance for the abrader device. This riser portion 24 provides a second deck 26 with parallel guides 21 (Figs. 3, 6) for directing a primary reciprocable table section 28. This table section 28 centrally therein carries a sleeve 29 about stem 30 which has a head 3| which functions as a nut for threaded stem 32. Bolt 33 mounts collar 34 on the riser portion 24 remote from the riser portion 2. Extending from this collar 34 is a tubular guide 35. Washer 36 is thrust toward the collar 34 by a helical spring 31 on the stem 32 and anchored thereto by pin 38. There is a tendency to draw the threaded stem 32 outward and such movement is limited by washer 39 held by nut 40 on the opposite side of the collar 34. Set screw 4I in a groove 42 may lock the angular position of disk 43 carrying handle 44. This tubular portion 35 carries a pointer 45 for scale 46 (Fig. 1) carried by the disk 43. Within this upright 24 is a pivot pin or fulcrum 41 (Fig. 2) for lever 48, located in proximity to the threaded stem 32 between the nut 40 and nut 49. This lever 48 extends from this fulcrum 41 not only past the stem 32 but through opening 50 in the riser portion 24 to protrude as a handle. This is a manual means for overcoming the action of the helical spring 31 in shifting the table 28 toward the abrader.

On the sleeve 29 there is an eccentric 5I (Figs. 3, 4) having a connection by screw 52 with the knurled cap 53 permitting manual adjustment of this eccentric 5I rotatively on the sleeve 29, thereby to vary the position of block 54 which provides the bearing for the exterior of this eccentric 5I. After such adjustment is made, wing bolt 55 acting as a set screw may lock this block 54 to the eccentricl 5I at such adjusted position. This block 54 (Fig. 2) is directed by guides 56 in the secondary table 51. The position of this block 54 relative to the oscillable table section 51 is determined by astem 58 extending loosely through guide 59 (Fig. 3) in the table section 51 and carrying a knurled nut 60. This nut 60 is embraced by arms 6I from handle 62 which is fastened by bolts 63 to this oscillable frame 51. Nuts 64 on the stem 30 are spaced from the eccentric 5I by thrust bearing 65. There is thus freedom for oscillation of this secondary table 51. Upon swinging the handle 62 this oscillation is about the stem 30 as an axis.

Fixed with this oscillable table 51 toward the abrader is a seat or templet 66 anchored therewith by bolt 61 (Fig.- 6) and dowel pin 68. 'I'he angular position for this templet 66 is thus` fixed. From this seat 66 there arises stem 69 terminally threaded in this seat 66 and upwardly carrying a shoulder providing enlargement 10 and an operating handle 1I. About this stem 69 is an externally threaded sleeve 12 having a key way 13 engaged by a screw key 14 of cross arm device 15. The rotation of the handle 1I (Figs. 1, 3) counter-clockwise will release the sleeve 12 so that the cross arm device 15 may be given a desired angular relation. An operation of this handle 1I clockwise then clamps this sleeve 12 so that the cross arm device 15 may not be angularly shifted but it is free to move axially. Knurled nut 16 on this threaded sleeve 12 may be eiiective as a clamp to thrust the cross arm device 15 down and hold such. This downward action is effective for engaging the Work. The cross arm device 15 has a central tubular portion and a pair of arms 11, terminally carrying clamp bolts 18 for clamping lingers 19, 88. It is thus possible to swing these clamping fingers 19 and 80 into desired angular relation relative to the cross arm device 15, and, as so held, bring such ngers 'I9 and 80 terminally against web 8| of brake shoe 82 having a brake gripping or engaging surface 83 to be dressed, finished or burnished.

In the carrying out of work hereunder, there is a purpose in accurately locating the brake shoe 82 for the desired operation.. Index or pointer 84 is along graduations 85 (Fig. 2) proper for the radius dimension. Adjustment to bring the shoe 82 to medial position is desirably one which does not take place at the hand wheel 44 but at the nut 68 in thereby shifting the block 54 in the secondary table 51. 'Ihen as such refinement is determined, the set screw 55 may lock such eccentric 5|. It may be in order then to determine that the initial placing of the bra-ke shoe 82 is proper on this seat 66. As such is determined from the angular location of clamp 69 and the down clamp nut 16, matters may be in readiness for operation. The motor 8 may then be thrown in for starting and the handle 62 swung to and fro to have the abrader effective crosswise of the face to be burnished or nished as such face is shifted. In this operation the action of the abrading disk I6 is largely local to a definite radial point on such disk. Effective wearing down of the disk I6 throughout its entire diameter is 40 possible hereunder by varying this radial position of the work as to the disk i6. This is effected by shifting of the motor 8, effected through the hand wheel 6. As there is similarity for a set of brake shoes in the placing or running through aJset 4 5 it is only necessary to release the nut 16, re-

move the brake shoe 82, and replace it by the substitute or succeeding shoe to be dressed. I In the carrying out of the invention herein, it is desirable that the terminal portions 86 of 50 the brake shoe 82 be beveled off or skived and this operation is preferably one which occurs before the dressing of the intermediate portion of the brake shoe 82. Lever 48 may be operated when the handle 62 has located a terminal por- 55 tion 86 of the brake shoe 82 in the vicinity of the abrading tool I6.

In the initial placing of the table 51 as determined by the pointer 84 on the scale 85, such may be taken as an initial position effected 60 through the operation of the hand wheel 44. For facilitating subsequent operation, say with other similarly dimensioned shoes, it may be ad- Vantageous to back off the set screw 4I, thereby releasing the disk 43 so that its set position will 65 be such that the scale 46 will read zero at the pointer 45. Accordingly, there is facility for ready subsequent placing or noting this departure from such initial placing in the event there be occasion to shift the reciprocab-le or primary table 70 or carrier section 28 mounting the secondary or oscillating table or carrier 51.

It is to be noted (Fig. '1) that the plate 66 is of diiierent length from the shoe 82 being acted upon. In the disclosure in this case, it is thus to be noted that the plate 66 may be for a range of different shoes and that these shoes may depart therefrom as to the arc extent even to be less, equal to or greater than the over all length of the arc of the plate 66. However, in practice it is usually desirable that the plate 66 be of an extent shorter than that of the shoe being acted upon. Thereby it is eiective to allow the ends of the shoes 82 to become deformed.

What is claimed and it is desired to secure by United States Letters Patent is:

l. A power tool comprising an abrading disk, a deck adjacent the disk, work holding means on said deck including a pivot bearing, an adjustable eccentric on the bearing, and a carrier mounted on said eccentric to swing relatively to the disk on said bearing as a pivot, whereby diiferent positions for the carrier on the eccentric determine different radius arc relationships for the work to be acted upon by the abrading disk.

2. A power tool comprising an abrading disk, a deck adjacent the disk, work holding means on said deck including a pivot bearing, an adjustable eccentric on the bearing, a carrier mounted on said eccentric to swing relatively to the disk on said bearing as a pivot and a work locating clamp on the carrier, whereby different positions for the carrier on the eccentric determine different radius arc relationships for the work to be acted upon by the abrading disk.

3. A power tool comprising an abrading disk, a deck adjacent the disk, work holding means on said deck including a pivot bearing, an adjustable eccentric on the bearing, a carrier mounted on said eccentric to swing relatively to the disk on said bearing as a pivot, a primary locating clamp on the carrier, and a secondary clamp on the carrier coaxial with the primary clamp and independently brought to gripping position for positioning work, whereby different positions for the carrier on the eccentric determine different radius arc relationships for the work to be acted upon by the abrading disk.

4. A power tool comprising an abrading disk, a deck adjacent the disk, work holding means on said deck including a pivot bearing, an adjustable eccentric on the bearing, a carrier mounted on said eccentric `to swing relatively to the disk on said bearing as Aa pivot, a work locating clamp on the carrier, and a plurality of swingable lingers positioned by said clamp, whereby diiferent positions for the carrier on the eccentric determine diiferent radius arc relationships for the work to be acted upon by the abrading disk.

5. A power tool comprising an abrading disk, a deck adjacent the disk, work holding means on said deck including a pivot bearing, an adjustable eccentric on the bearing, a carrier mounted on said eccentric to swing relatively to the disk on said bearing as a pivot, a work locating clamp on the carrier, and a plurality of swingable fingers positioned by said clamp, there being an adjustable mounting for the fingers, whereby different positions for the carrier on the eccentric determine diierent radius arc relationships for the work to be acted upon by the abrading disk.

HARRY K. BIGELOW. 

